Quote:
Originally Posted by camaro_corvette
I would first check your tires. My mom just bought an Impala and she was getting terrible mileage in it, well er, for an impala. I checked her tires and they were all above 40. Door asks for 32? So I put the tires to what the door and the manual says to put in it. She hasn't ran a tank of gas through it yet, so hopefully she gets better results. So far the computer is saying that we are breaking the 30's now consistently. I hope it is right.
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She should get better mileage with the 40 psi. Higher air pressure equals less rolling resistance equals better mpg.
As to the original question, in time the motor will make more power and you will get better mpg. I wouldn't worry about it, the manufacturer's estimates are usually spot on or even low. If you never achieve their estimates, it probably has more to do with your driving habits than anything else. I'm not being critical of your driving, just stating the most obvious culprit.
Either way, enjoy! 20 mpg and 400hp is pretty damn good!